Carbon-brush holder for electric machines



(No Model.)

W. E. KNOWLTON. CARBON BRUSH HOLDER FOR ELECTRIC MACHINES.

N0. 558,184. Patented Apr. 14, 1896.

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94. a 9M WM zxmm UNITED STATES PATENT ()FEIcE,

IVILLIAM E. KNOlVLTON, OF PORTLAND, MAINE.

CARBON-BRUSH HOLDER FOR ELECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent N 0. 558,184, dated. April14, 1896.

Application filed February 19, 1896. Serial No. 579,872. (No model.)

To all whom it may concern.-

Be it known that 1, WILLIAM E. KNowLToN, a citizen of the United States,residing at Portland, in the county of Cumberland and State of Maine,have invented certain new and useful Improvements in Carbon-BrushHolders for Electric Machines; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same.

My invention relates to an improved form of carbon-brush l1 older'forelectric generators, dynamos, &c., where a commutator is used, and itparticularly relates to an improved construction of a carbon-brushholder now in common use on generators of large size.

In the brush-holder referred to there is a clamp mounted on thebrush-holder stud so held that it may be loosened and turned on saidstud. The brush is held on end against the commutator by a socket, whichis connected to the clamp by parallel fiat rods. The brush extendsentirely through said socket, and its outer end is acted on bya fiatspring, one end of which is rigidly secured to the clamp. IVhen it isdesired to remove the brush from its socket for the purpose of renewingit or of cleaning its contact-surface, the entire brush-holder isrotated 011 the stud until the brush is free from the commutator and thebrush is then slipped out from the under side of the socket. Theprincipal difficulty which has been experienced with this brushholder isthat if the socket is tilted back, the

-brush removed, and the contact-surface of commutator will not beperfect.

the carbon cleaned, as must frequently be done when the machine isrunning, if the socket is not replaced in exactly the same position withrelation to the commutator that it was before, the contact of the brushwith the The friction of the end of the brush with the surface of thecommutator wears it in the form of a cylindrical surface having the samecurve as the surface of the commutator, and if any dirt gets in betweenthe end of the brush and the commutator it is necessary to remove theformer and clean it, and this operation is usually done while themachine is running. As already stated, if the position of the socketwhen the carbon is replaced is nearer or farther away from thecommutator the end of the carbon will not fit the surface of thecommutator and a new surface will have to be worn before the contactwill be perfect. Another difficulty with this brush-holder is that inlarge generators, where the brush-holders are out of easy reach, it isdiflicult to remove the brushes when the machine is in motion, and theoperation is always a dangerous one.

My improvement on the brush-holder described consists in pivoting theend of the spring which is connected with the clamp so that the oppositeend can be swung aside from the outer end of the carbon brush,permitting the brush to be removed through the outer end of the socketand without disturbing the position of the latter with relation to thesurface of the commutator.

In the accompanying drawings I have illustrated a brush-holder embodyingmy invention, in which Figure 1 is a side view, and Fig. or top view.

A represents the surface of the commutator, and G is the brush-holderstud. (Shown in section in Fig. 1.) The carbon brush D is held incontact with the commutator by the socket C, which has an openingextending entirely through it, so that the outer end of the brushextends above the outer end of the socket. The socket is supported byand connected to a clamp F, which is clamped on the stud Gr by means, asherein shown, of parallel supporting bars or rods 15, which are securedrigidly by one end to the socket and by the other end to the clamp. Thefriction of the clamp on the stud is regulated by means of thebinding-screw f, which allows the clamp to be loosened so that it willturn on the stud.

According to my present invention the brush D is pressed inward againstthe surface of the commutator by means of the spring H, which is pivotedto the clamp F by one end, the opposite end bearing against the outerend of the brush. As herein shown, the spring II is pivoted a shortdistance from its end by a bolt j, which passes through it and into theclamp F, the spring being held down by a thumb-nut on the outer end onthe bolt. The extreme end of the spring II is bent down onto the uppersurface of the clamp F to form 2 a plan a bearing or fulcrum.

In the form of my invention which I have here shown I make use of areinforcing-spring I, the free end of which bears on the top of thespring II near its inner end, While the other end is secured firmly tothe clamp back of the end of the spring H.

WVhen it is desired to remove the brush for the purpose of cleaning orrenewing it, it is only necessary to swing the spring to one sideWithout loosening the clamp on the stud and without disturbing theposition of the socket with relation to the surface of the commutator,as is clearly shown in the dotted lines of Fig. 2.

By the use of myimproved brush-holder the brushes can be readily changedquickly and easily at any part of the commutator where they can bereached, and when the brush is put back in position it is absolutelycertain that the contact will be perfect and the efficiency of its workassured.

I claim- 1. The herein described carbon brush holder for electricmachines consisting of a socket for holding the brush on end against thecommutator, a clamp secured to the brushholder stud, bars or rods Bconnecting said socket with said clamp and a spring H pivoted by one endto said clamp,'the opposite end bearing on the outer end of said brushto press the same against the commutator.

2. The herein described carbon brush holder for electric machinesconsisting of a socket for holding the brush on end against thecommutator, a clamp secured to the brushholder stud, bars or rods Bconnecting said socket with said clamp a spring H one end of which bearson the outer end of said brush, the opposite end being pivoted to theclamp by a bolt near its end, the extreme end being bent down to bear onsaid clamp and an auxiliary spring I secured by one end to the saidclamp and having its free end bearing on the top of said spring II toreinforce the same.

WILLIAM E. KNOWLTON.

\Vitnesses:

S. \V. BATES, MARY S. CARLETON.

